Contributing writer The Transmitter Share this article: Tags: Vision, Brain mapping, Neurons, system neuroscience, Visual cortex Adrien Peyrache first encountered Yves Frégnac some 20 years ago. Peyrache, now associate professor at McGill University, had signed up for a graduate neuroscience class about the visual system, taught at École Normale Supérieure in Paris on Saturday mornings. On the first day of class, Frégnac showed up late and disheveled.